Surface Electrostatic Potentials of Polychlorinated Dibenzo-p-dioxins and Their Applications in the Quantitative Structure-properties Relationships

Polychlorinated dibenzo-p-dioxins(PCDDs) are a group of important persistent organic pollutants.They are highly toxic and persistent in environment.In the present study,geometrical optimization and electrostatic potential calculations have been performed for 75 PCDD congeners and dibenzo-p-dioxin(DD) at the HF/6-31G* level of theory.A number of statistically based parameters have been extracted.Linear relationships between vapor pressures(logpL),aqueous solubilities(logSw),n-octanol/water partition coefficients(logKow) of PCDDs and structural descriptors have been established by stepwise linear regression analysis.The result shows that the quantities derived from the surface electrostatic potentials Vmin,Π,and Vs,av+,together with Vmc(the molecular volume) and ELUMO(the energy of the lowest unoccupied molecular orbital) can be well used to express the quantitative structure-property relationships of PCDDs.Predictive capabilities of the models have also been demonstrated by leave-one-out cross-validation with the cross-validated correlation coefficient(Rcv) above 0.97.Based on these QSPR models,the predicted values have been presented for those PCDD congeners whose experimentally determined physicochemical properties are unavailable.